Debris removal system for a power tool

ABSTRACT

A powered hand tool includes a motor, a cutting member drivable to cut a workpiece, and a drive system interconnecting the motor and the cutting member and operable to drive the cutting member in response to operation of the motor. A housing at least partially encloses the cutting member and the motor and a debris removal system is movable between a first position and a second position. The debris removal system is operable to clean a portion of the drive system when in the second position. The debris removal system includes an abrasive member, an automatic actuator, and a sensor operable to selectively generate a signal. The automatic actuator is movable between an actuated position in which the abrasive member moves to the second position and a non-actuated position in which the abrasive member moves to the first position in response to the sensor.

RELATED APPLICATION DATA

This application is a continuation of U.S. application Ser. No.12/509,159 filed Jul. 24, 2009, now U.S. Pat. No. 8,397,390, whichclaims benefit under 35 U.S.C. Section 119(e) of U.S. ProvisionalApplication No. 61/083,732, filed Jul. 25, 2008, both of which are fullyincorporated herein by reference.

BACKGROUND

The present invention relates to a system for removing debris from powertool components, and more particularly, from band saw components.

Band saws may be various sizes to accommodate various cuttingapplications, and typically include a drive wheel pulley, a driven wheelpulley and a continuous saw blade positioned around the drive wheel andthe driven wheel. The saw blade is driven by the drive wheel to cut workpieces (e.g., metal, wood, etc.). As the saw blade cuts the work piece,the saw blade picks up chips (e.g., metal chips, wood chips, etc.),which can embed in a blade tire of the respective wheel. The embeddedchips may cause the saw blade to slip with respect to the blade tire andthe wheel. When debris embeds in the blade tire, the cuttingcapabilities of the band saw decrease, thereby requiring removal of theblade tire for replacement or cleaning.

SUMMARY

In one construction, the invention provides a powered hand tool thatincludes a handle portion arranged to provide a grip point for a user, amotor, a cutting member drivable to cut a workpiece, and a drive systeminterconnecting the motor and the cutting member and operable to drivethe cutting member in response to operation of the motor. A housing atleast partially encloses the cutting member and the motor and a debrisremoval system is movable between a first position and a secondposition. The debris removal system is operable to clean a portion ofthe drive system when in the second position.

In another construction, the invention provides a powered hand tool thatincludes a housing having a handle portion arranged to provide a grippoint for a user, a first blade tire rotatable about a first axis, and asecond blade tire rotatable about a second axis. The first axis and thesecond axis are positioned a non-zero distance from one another and arearranged substantially parallel to one another. A continuous saw bladeis positioned to extend around a portion of the first blade tire and aportion of the second blade tire and a motor is positioned at leastpartially within the housing and is operable to drive the first bladetire to move the blade along a continuous path to cut a workpiece. Adebris removal system has an abrasive member positioned substantiallywithin the housing and an actuator portion positioned at least partiallyoutside of the housing. The debris removal system is movable between afirst position and a second position in which the abrasive member isoperable to clean a portion of one of the first blade tire and thesecond blade tire.

In yet another construction, the invention provides a powered hand toolthat includes a first blade tire that is rotatable about a first axisand a second blade tire rotatable about a second axis. The first axisand the second axis are positioned a non-zero distance from one anotherand are arranged substantially parallel to one another. A continuous sawblade is positioned to extend around a portion of the first blade tireand a portion of the second blade tire and a motor is operable to drivethe first blade tire to move the blade along a continuous path to cut aworkpiece. An abrasive member is movable between a first position and asecond position in which the abrasive member contacts one of the firstblade tire and the second blade tire to remove debris produced duringthe cutting of the workpiece. An actuator portion is movable between anon-actuated position and an actuated position. Movement to the actuatedposition moves the abrasive member to the second position.

In another construction, the invention provides a powered hand tool thatincludes a handle portion arranged to provide a grip point for a user, amotor, a cutting member drivable to cut a workpiece, and a drive systeminterconnecting the motor and the cutting member and operable to drivethe cutting member in response to operation of the motor. A housing atleast partially encloses the cutting member and the motor and a debrisremoval system is movable between a first position and a secondposition. The debris removal system is operable to clean a portion ofthe drive system when in the second position. The debris removal systemincludes an abrasive member, an automatic actuator, and a sensoroperable to selectively generate a signal. The automatic actuator ismovable between an actuated position in which the abrasive member movesto the second position and a non-actuated position in which the abrasivemember moves to the first position in response to the sensor.

In yet another construction, the invention provides a powered hand toolthat includes a housing including a handle portion arranged to provide agrip point for a user, a first blade tire rotatable about a first axis,and a second blade tire rotatable about a second axis. The first axisand the second axis are positioned a non-zero distance from one anotherand are arranged substantially parallel to one another. A continuous sawblade is positioned to extend around a portion of the first blade tireand a portion of the second blade tire, a motor is positioned at leastpartially within the housing and is operable to drive the first bladetire to move the blade along a continuous path to cut a workpiece, and adebris removal system has an abrasive member positioned substantiallywithin the housing and an actuator portion positioned at least partiallyoutside of the housing. The debris removal system is movable between afirst position and a second position in which the abrasive member isoperable to clean a portion of one of the first blade tire and thesecond blade tire. The actuator portion includes a sensor and anautomatic actuator. The automatic actuator moves the abrasive memberfrom the first position to the second position in response to a signalfrom the sensor.

In another construction, the invention provides a method of cleaning apowered hand tool having a continuous saw blade. The method includesrotating a first blade tire to rotate the continuous saw blade and asecond blade tire, sensing a condition related to the powered hand toolthat is indicative of a level of debris collected during operation ofthe powered hand tool, and generating a signal in response to thecondition exceeding a predefined level. The method further includesmoving an automatic actuator from a non-actuated position to an actuatedposition in response to the signal and moving an abrasive member inresponse to movement of the automatic actuator from a first position toa second position in which the abrasive member is operable to clean aportion of one of the first blade tire and the second blade tire.

Other aspects of the invention will become apparent by consideration ofthe detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a band saw suitable for use with thedebris removal system;

FIG. 2 is a perspective view of a debris removal system incorporatedinto the band saw of FIG. 1;

FIG. 3 is another perspective view of the debris removal system of FIG.2 in a first or non-actuated position;

FIG. 4 is a perspective view of the debris removal system of FIG. 2, ina second or actuated position; and

FIG. 5 is a perspective view of an automatically actuated debris removalsystem incorporated into the band saw of FIG. 1.

Before any embodiments of the invention are explained in detail, it isto be understood that the invention is not limited in its application tothe details of construction and the arrangement of components set forthin the following description or illustrated in the following drawings.The invention is capable of other embodiments and of being practiced orof being carried out in various ways. Also, it is to be understood thatthe phraseology and terminology used herein is for the purpose ofdescription and should not be regarded as limiting.

DETAILED DESCRIPTION

FIGS. 1-4 illustrate a band saw 10 that includes a debris removal system94 according to one embodiment of the invention. FIG. 1 illustrates anAC version of the band saw 10 having an electrical connection cord 12.However, other embodiments may be applied to DC versions of the band saw10 which includes one or more rechargeable battery packs that arepreferably removable.

The band saw 10 includes a housing or frame 14 supporting a motor 18 anda drive system including a gear box 22. The motor 18 is drivinglyconnected to a drive mechanism (not shown) at least partially housedwithin the gear box 22. The motor 18 and the drive mechanism areoperable to drive a continuous band saw blade 26 to cut a work piece. Asdescribed herein, the band saw 10 includes a front 30 and a rear 34. Thefront 30 is defined as the side being proximate the portion of the bandsaw blade 26 that cuts the work piece and the rear 34 is defined as theside proximate the portion of the band saw blade 26 that does not cutthe work piece. The rear 34 is otherwise described as being opposite thefront 30.

The housing 14 includes a main handle 38 supporting a switch assembly 42to control power to the band saw 10. The switch assembly 42 is operableby the user to selectively control operation of the motor 18. The bandsaw 10 also includes an auxiliary handle 46 for a user's other hand.Generally, the handles 38, 46 are shaped and arranged for two-handedoperation of the band saw 10 as the work piece is cut. In theillustrated embodiment, each handle 38, 46 has an ergonomic design toprovide comfortable gripping and controlled operation of the band saw10. The ergonomic design of each handle 38, 46 and of the combination ofthe handles may include the orientation or angle of handle(s). Theergonomic design may also include the use of material, such as anelastomeric material, on the handle(s) 38, 46 to, one or more of,provide an improved grip surface, isolate vibration and impacts from theoperator, prevent heat build-up and/or transfer to the operator, etc.

The housing 14 defines a first portion 50 and a second portion 54. Thefirst portion 50 and the second portion 54 are spaced apart from oneanother and define a U-shaped cavity 66 defining a cut zone 58therebetween. A blade guard 62 (FIGS. 2-4) is positioned at the rear 34of the band saw 10 and extends between the first and second portions 50,54 within the cut zone 58. The blade guard 62 is positioned along therear 34 of the band saw 10 and provides a recessed area to house theband saw blade 26. In the illustrated embodiment, the blade guard 62extends parallel to the portion of the band saw blade 26 in the cut zone58 at the front 30 of the band saw 10.

As shown in FIGS. 2-4, the band saw 10 generally includes a drive wheelpulley 70 and a driven wheel pulley 71. The drive wheel 70 rotates abouta drive wheel axis 78 (shown in FIG. 2) and is drivingly connected tothe motor 18 via a drive system 79. The driven wheel 71 rotates about adriven wheel axis 82 and is rotatably supported by the housing 14. Thedrive wheel 70 is positioned in the first portion 50 of the housing 14,and the driven wheel is positioned in the second portion 54 of thehousing 14. A blade tire 86 is coupled to each of the peripheries of thedrive wheel 70 and the driven wheel 71. Each blade tire 86 is acircular-shaped ring formed of a soft and/or flexible elastomericmaterial that is able to lock or adhere to the respective wheel. Theband saw blade 26 extends around the drive wheel 70 and the driven wheel71 and is gripped by the blade tires 86. In this way, motion from thedrive wheel 70 is transmitted to the band saw blade 26 via the bladetires 86. The band saw 10 may also include a blade tensioning mechanism90 to adjustably provide appropriate tension on the band saw blade 26.The band saw may also include a shoe 92 for positioning against the workpiece.

The amount of grip or friction between the blade tires 86 and the bandsaw blade 26 depends, in part, on the tension in the band saw blade 26and on the coefficient of friction between the blade tire 86 and theblade 26. The greater the friction between the blade tires 86 and theband saw blade 26, the greater the pull force on the band saw blade 26by the blade tires 86 as the wheels rotate. The band saw blade 26 isdesigned to continuously loop about a circuit formed between the drivewheel 70 and the driven wheel 71. The band saw blade 26 generallyengages approximately 180 degrees of the circular blade tire 86, whilethe remaining approximately 180 degrees of the blade tire 86 isseparated from the band saw blade 26.

With reference to FIGS. 2-4, the band saw 10 includes a debris removalsystem 94 for cleaning debris from the blade tire 86. The debris may befrom chips (e.g., metal or wood chips) from the work pieces or anydebris that can be embedded into the elastomeric blade tire 86. Thedebris removal system 94 is positioned toward the rear 34 of the bandsaw 10, proximate the blade guard 62. The debris removal system 94 iscoupled to an underside of the first portion 50 of the housing 14 andincludes an abrasive 98 and a biasing member or spring 102 coupled tothe abrasive 98. The abrasive 98 is positioned in the first portion 50and adjacent to the blade tire 86 of the drive wheel 70 at a segment ofthe blade tire 86 that is not engaged with the band saw blade 26. In theillustrated embodiment, the abrasive 98 is a wire brush that scrapes theblade tire 86 to clean or remove debris therefrom. In other embodiments,the abrasive 98 is formed from a variety of materials or substrates thatprovide a roughened surface for contacting and cleaning the blade tire86.

The spring 102 is a flat spring (leaf spring) that biases the abrasive98 away from the blade tire 86, and includes a first end 114 and asecond end 116 (shown in FIG. 3). The spring 102 extends through anaperture 110 (FIG. 3) formed in the first portion 50 of the housing 14such that the first end 114 is positioned inside the first portion 50and the second end 116 is positioned outside the first portion 50 (i.e.,within the cavity 66). The first end 114 of the spring 102 is coupled tothe abrasive 98, and the second end 116 of the spring 102 is coupled tothe housing 14 using fasteners 106 or other suitable attachment means(e.g., adhesive, clamps, etc.). In other embodiments, the spring 102 ispositioned anywhere on the housing such that the abrasive 98 is able toengage the blade tire 86. In still other embodiments, the wheel is opento the cavity 66 and the spring 102 and the abrasive 98 are positionedin the cavity to engage with the blade tire 86 of the wheel. The drivewheel 70, and therein the blade tire 86, rotate such that the abrasive98 removes debris from the blade tire 86 as the drive wheel 70 rotates,and in some embodiments, prior to engagement of the blade tire 86 withthe band saw blade 26.

With continued reference to FIGS. 2-4, the debris removal system 94further includes an actuator or button 118 and an actuator spring 122compressed by the actuator 118. The actuator 118 is substantiallycylindrical shaped, and includes a first hub 126 and a second hub 130positioned at opposing ends of the actuator 118. The first hub 126provides an area for a user to manipulate the actuator 118, and thesecond hub 130 is positioned proximate the spring 102 for engaging andmoving the spring 102. The actuator 118 is movable between a firstposition in which the actuator 118 does not displace the spring 102 anda second position in which the actuator 118 engages and displaces thespring 102. The abrasive 98 engages the blade tire 86 in response tomovement of the actuator 118 to the second position. When the actuator118 is released, the actuator spring 122 biases the actuator 118 to thefirst position and the spring 102 biases the abrasive 98 to thenon-contact position illustrated in FIG. 2. In other embodiments, otheractuators may be used to engage the abrasive 98 with the blade tire 86.

The actuator spring 122 is a coil compression spring, and is positionedaround the actuator 118 and compressed between the first hub 126 and ashoulder 134 of the debris removal system 94 that is proximate thehousing 14. The actuator spring 122 biases the actuator 118, and inparticular the second hub 130, away from the spring 102. FIGS. 2 and 3illustrate the actuator 118 in a neutral or release position biased awayfrom the spring 102 by the actuator spring 122. To engage the abrasive98 with the blade tire 86, and thereby move the actuator 118 into acleaning position (shown in FIG. 4), the actuator 118 (i.e., the firsthub 126) is pressed by a user's hand, as shown in FIG. 4. The forceapplied by the user causes the actuator 118 to move toward the spring102 against the biasing force of the actuator spring 122. The second hub130 of the actuator 118 pushes the spring 102 against the biasing forceof the spring 102 until the abrasive 98 engages the blade tire 86 toremove debris from the tire 86.

In some embodiments, an automated debris removal system 199 is employed.For example, FIG. 5 illustrates a construction in which a sensor 200 ispositioned adjacent the blade tire 86 to count revolutions of the bladetire 86. A controller 205, such as a simple micro-controller orintegrated circuit includes a counter that counts the revolutions of theblade tire 86 and generates a signal when the number of revolutionsexceeds a predetermined number. The controller 205 then resets thecounter to zero and begins counting again. The signal is transmitted toan electromechanical device 210 such as a solenoid, a motor, apiezoelectric element, or, as illustrated in FIG. 5, a simpleelectromagnet arrangement. In the construction of FIG. 5, theelectromechanical device 210 is positioned adjacent the leaf spring 102.The signal from the controller 205 actuates a switch 215 that energizesthe electromechanical device 210. A permanent magnet 220 may be attachedto the leaf spring 102 to assure that when the electromechanical device210 is energized, the leaf spring 102 is repelled rather than attracted.After a predetermined time period or a predetermined number ofrevolutions, the electromechanical device 210 is deenergized and thecycle repeats. Thus, in the automated construction of FIG. 5, the userdoes not need to actuate the debris removal system. Rather, the systemautomatically periodically removes debris.

In other automated systems, the leaf spring 102 may be arranged to biasthe abrasive member 98 into contact with the blade tire 86. In theseconstructions, the electromechanical device 210 is energized whencleaning is not occurring. While this arrangement is possible, it wouldresult in reduced battery life or additional power consumption.

In other embodiments, the debris removal system 94 (manual or automatic)can be positioned at other points along the exposed portion of the bladetire 86 of the drive wheel 70 such that the abrasive 98 cleans the bladetire 86 prior to engagement with the band saw blade 26. In still otherembodiments, the debris removal system 94 is coupled to the secondportion 54 of the housing 14 and the abrasive 98 is positioned proximatethe blade tire of the driven wheel 71. In yet another embodiment, theband saw 10 includes more than one debris removal system 94 for removingdebris from either or both of the blade tires.

In operation, the band saw blade 26 rotates about the drive wheel 70 andthe driven wheel. The drive wheel 70 is driven by the motor 18 and thedrive system or mechanism. As the drive wheel 70 rotates, the blade tire86 frictionally engages or grips the band saw blade 26 to transmit therotational movement of the drive wheel 70 to the band saw blade 26. Themovement of the band saw blade 26 cuts a work piece and, in some cases,produces debris (e.g., chips). The debris is prone to enter the housing14 and attach to or embed in the blade tire 86.

To remove the debris and clean the blade tire 86, the debris removalsystem 94 can be periodically actuated by a user while the band saw isoperating. As shown in FIG. 4, a user presses the actuator 118 to moveit toward the second position against the biasing force of the actuatorspring 122. The second hub 130 of the actuator 118 contacts the secondend 116 of the abrasive spring 102 and forces (i.e., deflects) theabrasive spring 102 toward the blade tire 86. The abrasive 98 engagesthe blade tire 86, and begins to scrape and remove debris on or embeddedin the blade tire 86. In the illustrated embodiment, the debris removalsystem 94 removes debris when the band saw blade 26 is in operation.However, other embodiments may include a system that removes debris whenthe band saw 10 is turned OFF.

In constructions that employ the automated debris removal system 194 ofFIG. 5, the user simply uses the band saw as if it had no system 199.The sensor 200 detects each revolution of the blade tire 86 and thecounter counts those revolutions. Once the number of revolutions exceedsa predetermined number, the micro-controller 205 generates a signal toclose a switch 215 (e.g., transistor, relay, etc.) and energize theelectromechanical device 210. The electromechanical device 210 ispositioned adjacent the permanent magnet 220 arranged to have the samepolarity as the electromechanical device 210 when energized. Thus, theelectromechanical device 210 repels the permanent magnet 220 and theleaf spring 102 to which it is attached to push the abrasive member 98into contact with the blade tire 86 to clean the blade tire 86. A timeror the sensor 200 and counter assures that the abrasive 98 remains incontact with the blade tire 86 for a sufficient time or a sufficientnumber of revolutions before the electromechanical device 210 isdeenergized.

Removal of debris from the blade tires 86 reduces band saw bladeslippage and reduces the likelihood of the blade 26 falling off thedrive wheel 70 and/or the driven wheel 71. Debris reduces thecoefficient of friction between the blade tire 86 and the blade 26 anddegrades the pull force on the blade 26 from the blade tires 86, therebydecreasing the cutting capability of the blade 26. By removing thedebris, the gripping capabilities and the coefficient of frictionincrease such that the blade tire 86 is able to transmit rotation andthereby maintain the cutting force provided by the band saw blade 26.

In other embodiments, the actuator 118 is alternately positioned inanother position on the band saw 10, such as, for example, on a top side182 (FIG. 1) of the housing 14. In these constructions, a linkagearrangement may be employed to produce the desired movement of theabrasive member.

In still other embodiments, the abrasive 98 is formed of a material thatallows the abrasive 98 to remain in constant engagement with the bladetire 86. In a further embodiment, the abrasive 98 is coupled to the bandsaw 10 in an engaged position against the blade tire 86 such that useractuation of the debris removal system is not required. For example, ascraper could be positioned immediately adjacent the blade tire 86 or inconstant contact with the blade tire 86 to continuously remove debris.

In the embodiment of FIGS. 1-5, the abrasive 98 engages the blade tire86 when the debris removal system 94 is actuated. In other embodiments,the abrasive 98 is partially engaged with the blade tire 86 when in aneutral or release position and is able to remove some debris, and whenthe debris removal system 94 is fully engaged with the blade tire 86,the abrasive 98 removes all or most of the debris.

In other embodiments, the debris removal system is used on a variety ofpower tools that have moving components affected by debris embedding orattaching to those components.

Although particular constructions embodying independent aspects of thepresent invention have been shown and described, other alternativeconstructions will become apparent to those skilled in the art and arewithin the intended scope of the independent aspects of the presentinvention.

What is claimed is:
 1. A powered hand tool comprising: a handle portionarranged to provide a grip point for a user; a motor; a cutting memberdrivable to cut a workpiece; a drive system interconnecting the motorand the cutting member and operable to drive the cutting member inresponse to operation of the motor; a housing at least partiallyenclosing the cutting member and the motor; and a debris removal systemmovable between a first position and a second position, the debrisremoval system operable to clean a portion of the drive system when inthe second position; wherein the debris removal system includes anabrasive member, an automatic actuator, and a sensor operable toselectively generate a signal, and wherein the automatic actuator ismovable between an actuated position in which the abrasive member movesto the second position and a non-actuated position in which the abrasivemember moves to the first position in response to the sensor.
 2. Thepowered hand tool of claim 1, wherein the cutting member is a blade andthe drive system includes a first blade tire and a second blade tirearranged to drive the blade along a closed continuous path, and whereinthe first blade tire is a drive tire driven by the motor to drive theblade along the closed continuous path.
 3. The powered hand tool ofclaim 2, wherein the abrasive member is positioned to contact the firstblade tire when in the second position to remove debris from the firstblade tire.
 4. The powered hand tool of claim 1, further comprising amicro-controller and a switch, and wherein the micro-controller receivesthe signal from the sensor.
 5. The powered hand tool of claim 2, whereinthe sensor senses the revolutions of one of the first blade tire and thesecond blade tire and generates the signal in response to the number ofrotations exceeding a predetermined number of revolutions.
 6. Thepowered hand tool of claim 1, wherein the automatic actuator includes anelectromagnetic device that energizes in response to the signal to movethe abrasive member to the second position.
 7. The powered hand tool ofclaim 1, wherein the automatic actuator includes a biasing membercoupled to an actuator to bias the automatic actuator toward thenon-actuated position.
 8. The powered hand tool of claim 1, wherein theabrasive member includes a wire brush and a leaf spring, the leaf springsupporting the wire brush and connected to the housing in a cantileverfashion, wherein the leaf spring biases the wire brush toward the firstposition.
 9. The powered hand tool of claim 8, wherein the housingincludes a stop positioned to engage one of the leaf spring and the wirebrush when in the second position to inhibit further movement toward thedrive system.
 10. A powered hand tool comprising: a housing including ahandle portion arranged to provide a grip point for a user; a firstblade tire rotatable about a first axis and a second blade tirerotatable about a second axis, the first axis and the second axispositioned a non-zero distance from one another and arrangedsubstantially parallel to one another; a continuous saw blade positionedto extend around a portion of the first blade tire and a portion of thesecond blade tire; a motor positioned at least partially within thehousing and operable to drive the first blade tire to move the bladealong a continuous path to cut a workpiece; and a debris removal systemhaving an abrasive member positioned substantially within the housingand an actuator portion positioned at least partially outside of thehousing, the debris removal system movable between a first position anda second position in which the abrasive member is operable to clean aportion of one of the first blade tire and the second blade tire,wherein the actuator portion includes a sensor and an automaticactuator, and wherein the automatic actuator moves the abrasive memberfrom the first position to the second position in response to a signalfrom the sensor.
 11. The powered hand tool of claim 10, wherein theabrasive member is positioned to contact the first blade tire when inthe second position to remove debris from the first blade tire.
 12. Thepowered hand tool of claim 10, wherein the sensor senses the revolutionsof one of the first blade tire and the second blade tire and generates asignal in response to the number of revolutions exceeding apredetermined number of revolutions.
 13. The powered hand tool of claim10, wherein the automatic actuator includes an electromagnetic devicethat energizes in response to the signal to move the abrasive member tothe second position.
 14. A method of cleaning a powered hand tool havinga continuous saw blade, the method comprising: rotating a first bladetire to rotate the continuous saw blade and a second blade tire; sensinga condition related to the powered hand tool that is indicative of alevel of debris collected during operation of the powered hand tool;generating a signal in response to the condition exceeding a predefinedlevel; moving an automatic actuator from a non-actuated position to anactuated position in response to the signal; and moving an abrasivemember in response to movement of the automatic actuator from a firstposition to a second position in which the abrasive member is operableto clean a portion of one of the first blade tire and the second bladetire.
 15. The method of claim 14, wherein sensing a condition includescounting the number of rotations of one of the first blade tire and thesecond blade tire.
 16. The method of claim 15, wherein the predefinedlevel is a predefined number of rotations.
 17. The method of claim 14,wherein moving the automatic actuator includes energizing anelectromagnetic device in response to the signal to move the abrasivemember to the second position.
 18. The method of claim 14, furthercomprising biasing the automatic actuator toward the non-actuatedposition.
 19. The method of claim 14, further comprising supporting theabrasive member with a leaf spring, the leaf spring connected to ahousing in a cantilever fashion to bias the abrasive member toward thefirst position.
 20. The method of claim 19, further comprisinginhibiting movement of the leaf spring and the abrasive member beyondthe second position.